Computing devices, such as notebook computers, personal data assistants (PDAs), and mobile handsets, have user interface devices, which are also known as human interface device (HID). One user interface device that has become more common is a touch-sensor pad. A basic notebook touch-sensor pad emulates the function of a personal computer (PC) mouse. A touch-sensor pad is typically embedded into a PC notebook for built-in portability. A touch-sensor pad replicates mouse x/y movement by using two defined axes which contain a collection of sensor elements that detect the position of a conductive object, such as a finger. Mouse right/left button clicks can be replicated by two mechanical buttons, located in the vicinity of the touchpad, or by tapping commands on the touch-sensor pad itself. The touch-sensor pad provides a user interface device for performing such functions as positioning a cursor, or selecting an item on a display. These touch-sensor pads may include multi-dimensional sensor arrays for detecting movement in multiple axes. The sensor array may include a one-dimensional sensor array, detecting movement in one axis. The sensor array may also be two dimensional, detecting movements in two axes.
Another user interface device that has become more common is a touch screen. Touch screens, also known as touchscreens, touch panels, or touchscreen panels are display overlays which are typically either pressure-sensitive (resistive), electrically-sensitive (capacitive), acoustically-sensitive (SAW—surface acoustic wave) or photo-sensitive (infra-red). The effect of such overlays allows a display to be used as an input device, removing the keyboard and/or the mouse as the primary input device for interacting with the display's content. Such displays can be attached to computers or, as terminals, to networks. There are a number of types of touch screen technology, such as optical imaging, resistive, surface wave, capacitive, infrared, dispersive signal, and strain gauge technologies. Touch screens have become familiar in retail settings, on point of sale systems, on ATMs, on mobile handsets, on game consoles, and on PDAs where a stylus is sometimes used to manipulate the graphical user interface (GUI) and to enter data.
FIG. 1A illustrates a conventional touch-sensor pad. The touch-sensor pad 100 includes a sensing surface 101 on which a conductive object may be used to position a cursor in the x- and y-axes, or to select an item on a display. Touch-sensor pad 100 may also include two buttons, left and right buttons 102 and 103, respectively. These buttons are typically mechanical buttons, and operate much like a left and right button on a mouse. These buttons permit a user to select items on a display or send other commands to the computing device.
FIG. 1B illustrates a conventional linear touch-sensor slider. The linear touch-sensor slider 110 includes a surface area 111 on which a conductive object may be used to position a cursor in the x-axes (or alternatively in the y-axes). The construct of touch-sensor slider 110 may be the same as that of touch-sensor pad 100. Touch-sensor slider 110 may include a one-dimensional sensor array. The slider structure may include one or more sensor elements that may be conductive traces. Each trace may be connected between a conductive line and a ground. By being in contact or in proximity on a particular portion of the slider structure, the capacitance between the conductive lines and ground varies and can be detected. The capacitance variation may be sent as a signal on the conductive line to a processing device. For example, by detecting the capacitance variation of each sensor element, the position of the changing capacitance can be pinpointed. In other words, it can be determined which sensor element has detected the presence of the conductive object, and it can also be determined the motion and/or the position of the conductive object over multiple sensor elements.
One difference between touch-sensor sliders and touch-sensor pads may be how the signals are processed after detecting the conductive objects. Another difference is that the touch-sensor slider is not necessarily used to convey absolute positional information of a conducting object (e.g., to emulate a mouse in controlling cursor positioning on a display) but, rather, may be used to actuate one or more functions associated with the sensing elements of the sensing device.
In addition to detecting motion of the conductive object in one or two axes to control cursor movement, these conventional touch-sensor pads have been designed to recognize gesture features. One conventional touch-sensor pad includes methods for recognizing gestures made by a conductive object on a touch-sensor pad, as taught by U.S. Pat. No. 5,943,052 to Allen et al. The touch-sensor pad described in U.S. Pat. No. 5,943,052 recognizes scrolling gestures (as well as other gestures such as tapping, pushing, hopping, and zigzag gestures) by analyzing the position, pressure, and movement of the conductive object on the sensor pad during the time of a suspected gesture, and sends signals to a host indicating the occurrence of these gestures.
The touch-sensor pad described in U.S. Pat. No. 5,943,052 includes touch-sensor pad and packet processor, which determines the position of the conductive object, such as a finger, that is proximate to, or touching, a sensing surface. A finger is present if the pressure exceeds a suitable threshold value. This conventional touch-sensor pad also includes a scroll zone, having a central axis. After detecting a user running a finger on the touch-sensor pad in a direction substantially parallel to an axis running the length of the scroll zone, the processor software sends scrolling messages to the operating system or application that owns an active window of a graphical user interface (GUI). Conversely, the packet processing software is configured to not scroll on motions that are not substantially parallel to the axis of the scroll zone. This avoids unwanted interference with normal program functions. The packet processing software also stops scrolling when the user lifts the scroll-activating finger or moves the finger in a direction substantially perpendicular to the scroll zone. The scroll zone could be vertical, or horizontal, or otherwise located on the touch-sensor pad to enable access for the user and proper alignment with the location of scroll bar on the GUI.
FIG. 1C illustrates a conventional touch-sensor pad 100 having a vertical scroll zone 104. The touch-sensor pad 100 includes a sensing surface 101 on which a conductive object may be used to position a cursor in the x- and y-axes, or to select an item on a display. Touch-sensor pad 100 also includes vertical scroll zone 104. Vertical scroll zone 104 is a defined area on the sensing surface 101 that is dedicated to perform scrolling operations when the conditions for a scroll gesture are met. The vertical scroll zone 104, in particular, is used to perform scroll-up and scroll-down operations. If the absolute position of the finger in a first axis (X axis) is detected in the scroll zone 104, and the motion is detecting in a positive direction in a second axis (Y axis), a scroll-up gesture is recognized, and accordingly, a scroll-up operation will be performed. Similarly, if the absolute position in the X axis is in the scroll zone 104, and the motion is detected in a negative direction in the Y axis, a scroll-down gesture is recognized to perform the scroll-down operation.
FIG. 1D illustrates a conventional touch-sensor pad 100 having a horizontal scroll zone 105. Touch-sensor pad 100 also includes horizontal scroll zone 105. Horizontal scroll zone 105 is a defined area on the sensing surface 101 that is dedicated to perform scrolling operations when the conditions for a scroll gesture are met. The horizontal scroll zone 105, in particular, is used to perform scroll-left and scroll-right operations. If the absolute position of the finger in a first axis (Y axis) is detected in the scroll zone 105, and the motion is detecting in a positive direction in a second axis (X axis), a scroll-right gesture is recognized, and accordingly, a scroll-right operation will be performed. Similarly, if the absolute position in the Y axis is in the scroll zone 105, and the motion is detected in a negative direction in the X axis, a scroll-left gesture is recognized to perform the scroll-left operation.